What term is used to denote the embryonic stage that follows the morula, characterized by a formation of a hollow cavity?

The term that describes the embryonic stage following the morula, which is characterized by the formation of a hollow cavity, is indeed the blastula. At this stage, the embryo transforms from a solid ball of cells (the morula) into a hollow structure that consists of a single layer of cells surrounding a fluid-filled cavity called the blastocoel. This transition is a crucial step in embryonic development because it sets the stage for subsequent processes such as gastrulation, where the formation of germ layers occurs.

Understanding this developmental progression is key to studying embryology and developmental biology, as it marks significant transitions in the organization and differentiation of cells that will eventually lead to the formation of various tissues and organs in the organism.